reach_listContactsV1

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description should fully disclose behavioral traits. It mentions pagination and filtering but lacks details on pagination specifics (e.g., page size, total count), rate limits, authentication requirements, or what constitutes 'basic information'. The description is minimal for a tool with no annotation support.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences long, front-loaded with the main action, and contains no redundant information. Every sentence adds value: the first states the core purpose, the second elaborates on filters and pagination.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has no output schema, so the description should compensate by explaining return values. It only mentions 'a paginated list of contacts with their basic information' without specifying fields, default page size, or iteration instructions. This is insufficient for an agent to fully understand the tool's output.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description adds only that the list is paginated and can be filtered, which is already implied by the parameter descriptions. No additional semantic meaning beyond schema is provided.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'Get a list of contacts'. It specifies optional filters (group UUID, subscription status) and mentions pagination. While it doesn't explicitly distinguish from sibling tools like reach_listContactGroupsV1 or reach_listSegmentContactsV1, the name and description make its function clear.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description explains the filtering capabilities but does not provide guidance on when to use this tool versus alternatives like reach_listSegmentContactsV1 (which lists contacts in a segment) or reach_listContactGroupsV1. It mentions optional filters but lacks explicit usage context or exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.